- Direct Synthesis of Unsymmetrical Dithioacetals
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Dithioacetals are a frequently used motif in synthetic organic chemistry and have recently seen increasing attention as structural motif in promising antiviral agents against plant pathogens. Most existing reports, however, only discuss symmetrical dithioacetals. Examples of mixed dithioacetals are scarce and no general method for the selective synthesis of these compounds exists. Herein, a synthetically simple general one-step protocol was developed for the synthesis of a broad range of unsymmetrical dithioacetals consisting of one aromatic and one aliphatic thiol moiety from the corresponding aldehyde/thiol mixture. The mixed S,S-acetals were obtained in high yields, and a great variety of functional groups was tolerated. Kinetic control enabled an excellent selectivity in regard to the unsymmetrical dithioacetal.
- Bognar, Sabine,van Gemmeren, Manuel
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supporting information
p. 4859 - 4863
(2021/02/03)
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- Direct anodic (thio)acetalization of aldehydes with alcohols (thiols) under neutral conditions, and computational insight into the electrochemical formation of the acetals
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A versatile protocol for the production of acetals/thioacetals by means of direct electrochemical oxidation is developed here under neutral conditions, providing (thio)acetals with good functional group tolerance and a wide scope for both aldehydes and (thio)alcohols. DFT calculations reveal that direct electron transfer from the anode plays a key role in carbonyl activation during this acid free acetalization process.
- Liu, Caiyan,Shen, Yongli,Xiao, Zihui,Yang, Hui,Han, Xue,Yuan, Kedong,Ding, Yi
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p. 4030 - 4034
(2019/08/07)
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- An expeditious and efficient bromomethylation of thiols: Enabling bromomethyl sulfides as useful building blocks
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A facile and highly efficient method for the bromomethylation of thiols, using paraformaldehyde and HBr/AcOH, has been developed, which advantageously minimizes the generation of highly toxic byproducts. The preparation of 22 structurally diverse α-bromomethyl sulfides illustrates the chemo-tolerant applicability while bromo-lithium exchange and functionalization sequences, free radical reductions, and additions of the title compounds demonstrate their synthetic utility.
- Silva-Cuevas, Carolina,Paleo, Ehecatl,León-Rayo, David F.,Lujan-Montelongo, J. Armando
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p. 24654 - 24659
(2018/07/25)
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- Cyanuric chloride-catalyzed thioacetalization for organocatalytic synthesis of thioacetals
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The thioacetalization of aromatic aldehydes has been realized with broad diversity in the presence of various thiols and thiophenols using cyanuric chloride as an organocatalyst.
- Liu, Yaqin
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p. 679 - 682
(2016/05/09)
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- Chemoselective and odorless transthioacetalization of acetals using α-oxo-ketene dithioacetals as thiol equivalents
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Using α-oxo-ketene dithioacetals 1a as odorless thiol equivlents, an efficient and odorless transthioacetalization of acetals 2 has been developed. In the presence of MeCOCl in MeOH, the cleavage of 1a commences to generate thiols at both room and reflux temperatures, and the generated thiols then react with acetals 2 to give correspecting thioacetals 3 in good yield. This transthioacetalization is characterized by mild reaction conditions, simple procedure, good yields, and perfect chemoselectivity. It is noteworthy that only a very faint odor of thiols can be perceived during both the reaction and workup.
- Yu, Hai-Feng
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p. 1280 - 1286
(2013/04/10)
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- Silica-supported phosphorus pentoxide: A reusable catalyst for S,S-acetalization of carbonyl groups under ambient conditions
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Phosphorus pentoxide supported on silica gel (P2O 5/SiO2) efficiently acts as a highly active and reusable catalyst for cyclic and non-cyclic S,S-acetalization of a variety of carbonyl compounds under mild, solvent-free an
- Shaterian, Hamid Reza,Azizi, Kobra,Fahimi, Nafiseh
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experimental part
p. 85 - 91
(2012/01/06)
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- Selenonium ionic liquid as an efficient catalyst for the synthesis of thioacetals under solvent-free conditions
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Acidic ionic liquid butyl ethyl phenyl selenonium tetrafluoroborate, [BEPSe]BF4, was successfully employed as a catalyst for the synthesis of several dithioacetals in the absence of a solvent. The method is general and selectively afforded thioacetals derived from aldehydes and ketones in good yields.
- Lenard?o, Eder J.,Borges, Elton L.,Mendes, Samuel R.,Perin, Gelson,Jacob, Raquel G.
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p. 1919 - 1921
(2008/09/19)
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- A mild and chemoselective dithioacetalization of aldehydes in the presence of anhydrous copper (II) sulfate
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Various aldehydes have been protected with different thiols as dithioacetals with excellent yields using anhydrous copper sulfate as a mild and chemoselective catalyst. The reaction is carried out in a solvent and/or under solvent-free conditions. The transthioacetalization of oxyacetals into dithioacetals was also achieved in an excellent yield. Copyright Taylor & Francis Group, LLC.
- Moghaddam, Firouz Matloubi,Bardajee, Ghasem Rezanejade,Oskui, Afsane Arefi
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p. 1445 - 1450
(2007/10/03)
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- 2,4,4,6-Tetrabromo-2,5-cyclohexadienone (TABCO), N-bromosuccinimide (NBS) and bromine as efficient catalysts for dithioacetalization and oxathioacetalization of carbonyl compounds and transdithioacetalization reactions
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The use of 2,4,4,6-tetrabromo-2,5-cyclohexadienone (TABCO), N-bromosuccinimide (NBS), and bromine as efficient catalysts for conversion of carbonyl compounds to their cyclic and acyclic dithioacetals and 1,3-oxathiolanes under mild reaction conditions are described. These catalysts are also used for efficient transdithioacetalization of acetals, diacetals, ketals, acylals, enamines, hydrazones, and oximes with high yields in the presence of thiols.
- Iranpoor, Nasser,Firouzabadi, Habib,Shaterian, Hamid Reza,Zolfigol
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p. 1047 - 1071
(2007/10/03)
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- Neutral lithium triflate (LiOTf) efficiently catalyzes chemoselective preparations of cyclic and acyclic dithioacetals from carbonyl compounds, acylals, and O,O-cyclic and open-chain acetals under solvent-free conditions
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An efficient and chemoselective preparation of cyclic and acyclic thioacetals from carbonyl compounds, cyclic and acyclic acetals and acylals in the presence of catalytic amounts of neutral lithium triflate and thiols under solvent-free conditions is described.
- Firouzabadi, Habib,Eslami, Shahram,Karimi, Babak
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p. 2401 - 2406
(2007/10/03)
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- Lithium bromide-catalyzed highly chemoselective and efficient dithioacetalization of α,β-unsaturated and aromatic aldehydes under solvent-free conditions
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Chemoselective dithioacetalization of aromatic- and α,β- unsaturated aldehydes in the presence of other structurally different aldehydes and ketones was achieved efficiently in the presence of catalytic amounts of LiBr under solvent-free conditions. Due to the neutral reaction conditions, this method is compatible with acid sensitive substrates.
- Firouzabadi, Habib,Iranpoor, Nasser,Karimi, Babak
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- Lithium trifluoromethanesulfonate (LiOTf) as a highly efficient catalyst for chemoselective dithioacetalization of carbonyl compounds under neutral and solvent-free conditions
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Various types of carbonyl compound can be efficiently and chemoselectively converted to their corresponding dithioacetals in the presence of catalytic amounts of lithium triflate under solvent-free conditions. Due to the neutrality of the reaction medium, this method is especially useful for acid sensitive substrates.
- Firouzabadi, Habib,Karimi, Babak,Eslami, Shahram
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p. 4055 - 4058
(2007/10/03)
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- TETRACHLOROSILANE CATALYZED DITHIOACETALIZATION
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Tetrachlorosilane was found to be a mild as well as selective catalyst for dithioacetalization of the carbonyl compounds.
- Ku, Bonchul,Oh, Dong Young
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p. 433 - 438
(2007/10/02)
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- Synthesis of Dithioacetals from Carbonyl Compounds and Thiols in the Presence of Polyphosphoric Acid Trimethylsilyl Ester (PPSE)
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Dithioacetals were synthesized from carbonyl compounds and thiols in the presence of polyphosphoric acid trimethylsilyl ester (PPSE).Aldehydes, ketones, and trioxane could be used as carbonyl compounds, and aromatic, primary, secondary, and tertiary thiols were applicable in the present reaction.The reaction between cyclohexanone and t-butyl thiol afforded a mixture of corresponding dithioacetal and t-butylcyclohexenylsulfide.
- Kakimoto, Masa-aki,Seri, Takuya,Imai, Yoshio
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p. 164 - 166
(2007/10/02)
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Dibenzyl disulfide is deprotonated at -78° approximately 7.5 times more rapidly than dibenzyl sulfide, as predicted by a molecular orbital analysis which focuses on the interaction between the carbon lone pair and an adjacent σ * orbital.
- Wolfe, Saul,Schirlin, Daniel
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p. 827 - 830
(2007/10/02)
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